When dialing in my MK4 printer to match the print quality of my Mk3S+'s, I noticed that the MK4 part cooling was inconsistent. Upon further examination, it became clear that the positioning of the MK4 hotend fan was creating turbulence/drafts at the nozzle and affecting part cooling.
I made this hotend fan shield so that the weak vacuum created by the hotend cooling fan does not create eddies in the vicinity of the nozzle. This part has noticeable positive affect when printing materials and geometries that are sensitive to overcooling.
I printed mine in ASA for thermal stability and light weight; no supports.
The author marked this model as their own original creation.